A rotary regenerative heat exchanger of the type defined herein comprises a cylindrical trunnion that supports an axially aligned rotor carrying a mass of heat absorbent material. The rotor is rotated about its axis in order that the heat exchange material therein may alternately be moved between hot and cold fluids flowing therethrough. Consequently, heat absorbed from the hot fluid is transferred to the cold fluid through the intermediary of the heat absorbent material carried by the rotor.
Inasmuch as the several fluids flowing through the heat absorbent material of the rotor are maintained at various pressure levels, there is a great tendency toward leakage between the compartments containing the high pressure fluid and the low pressure fluid. Even when provided with suitable sealing means between relatively movable parts of the rotor, some leakage of fluid will occur, and when the temperature of the leakage may range from 1250.degree. F. to 1500.degree. F., extensive damage may be effected by the hot fluid after it has leaked from its normal containment chamber.
For these reasons effective sealing means must be incorporated into the heat exchanger, and to be particularly effective for the sealing of high temperature fluids, some arrangement must be included in the sealing arrangement for effectively cooling the leakage fluid to a temperature that will not adversely affect surrounding materials, when such leakage does occur.
Sealing means that attempts to preclude the leakage of gas from a rotary regenerative preheater was disclosed by U.S. Pat. No. 3,822,738 of July 9, 1974, issued to Hermann E. Kurschner, and by U.S. Pat. No. 3,980,128 of Sept. 14, 1976, issued to Richard F. Stockman. In both of these patents some provision was made for a seal permitting simultaneous radial and axial movement of the relatively movable sealing elements, however no arrangement was disclosed for cooling or otherwise neutralizing the leakage fluid that was bound to occur.